


The Heat

by JuHuaTai



Series: A/B/O AU [1]
Category: One Piece
Genre: Alpha!Marco, Alpha/Beta/Omega Dynamics, Dubious Consent, Explicit Sexual Content, M/M, Omega!Ace, Semi-Canon Compliant, Semi-PWP
Language: English
Status: Completed
Published: 2018-03-09
Updated: 2018-03-10
Packaged: 2019-03-29 02:36:15
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 14,406
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13917579
Author URL: https://archiveofourown.org/users/JuHuaTai/pseuds/JuHuaTai
Summary: “Ace, do you even know what secondary genders are?”“Yeah, i remember it. Alpha, Beta and Omega, wasn’t it? What about them?”“What about them— Ace, do you even know how secondary gender works?”“Uh, i think it was something like Alpha is the strongest, Beta is average and Omega is weak, or something? I don’t know, that’s all i can remember. What does that have to do with getting a heatstroke?”-Growing up the way he did, Ace knew that there are common knowledge that people would know about that he missed out on. But it's okay, because he can count on Marco to teach him, one way or another. And maybe, along the way, he can teach Marco some things too.





	1. Part 1

**Author's Note:**

> Heyo, i’m having writer’s block and experiencing boredom while laid sick. Also, I saw an A/B/O fic earlier and tbh, i always wanted to try my hands on that, so here it is! 
> 
> Don’t expect much plot or one that makes sense, okay. It's kind of like the oh-so-imaginative title, in the grand scheme of things, this is literally just porn and probably not a very good one. I’m trying, alright?
> 
> Hope you'd enjoy!

 

The first time Ace knew about secondary gender, it was because of a dirty magazine one of the bandits hid inside of a tree trunk just outside of Dadan’s hideout.

 

The cover was glossy and the sharp colours hurts his eyes, but the thing that piqued his curiosity had been one of the featured pin-ups, starring ‘Selection of the Hottest Male and Female Omega Models’. There were so many new words there, he thought, but Sabo always knows everything so he’d know what it is. Thinking nothing else of it, he brought the magazine to the treehouse, eager to show his brothers of this new findings. 

 

Only, Sabo was just as stumped as he is.

 

“Why are they all naked?” was Luffy’s first question, turning and flipping the magazine upside down as if the answer would somehow fall on its own, “They’re all posing funny. Hey, hey, do you think this person is rubber too?”

 

Sabo stopped their younger brother from trying one of the position shown in the book, because he had been too close to the exit door and he didn’t want anyone rolling out of the treehouse and to the ground below, “I think i heard the word Omega from one of the guys before, but I’m not sure,” 

 

Ace snatched the book from Luffy’s hand, when the youngest in their trio suddenly found himself entangled with his own limbs while trying one of the weird poses, “Maybe we should ask Dadan about it,” he suggested after they finally managed to free Luffy from his own tangling arms, “This is probably one of those adult stuff that they keep on saying we gotta wait until we’re older to hear or something,”

 

It had been one of his worst ideas, because the moment they showed the magazine to the matron, she smacked the three of them with the magazine and punch no less than 10 of her bandits with her fist.

 

She told them that it was too young for them to know, but the three of them were nothing if not persistent. Finally, their reluctant caretaker relented, and slammed a funny looking book with red cover in front of them. There’s odd looking symbols on the front of it, and the large typing on the front of it reads ‘Learning A/B/O for Children’, “There, learn them yourselves. And remember, its your own fault for asking. Goddamn Garp, leaving me with these hooligans. Now they wanted me to teach them that kind of things, what the hell do i look like, a teacher?”

 

That night, they read it in the dim lights in their treehouse, huddling close in Sabo’s bed.

 

“It says here that while male or female is your primary gender, everyone also had their secondary gender. They’re called Alpha, Beta and Omega,” the blonde reads, eyes darting from one corner to another in the speed Ace could only hope to match. Luffy had long since given up trying to understand any of the words and simply plopped to his side, chewing on some leftover meat from their dinner.

 

“Just like our primary gender, our secondary gender is predetermined by our biology. They differ from people to people and we’d only what ours would be after we reached puberty, but there’s usually a common characteristic that makes it easy for you to find out what your secondary gender is even before,”

 

“Yeah, what are they?”

 

Sabo’s tongue peeked out from behind his lips as he flicked through the pages, humming in concentration. Didn’t take long for him to find the page he was looking for, “Alphas are usually big, physically strong, and a natural born leader. Betas are much more common, they are peace loving and neutral, and the most calm out of the three. Omegas are weaker and submissive, but they are strong in mind and drive,”

 

Ace cocked his head in confusion, turning to Sabo, “What does that mean?”

 

The ‘middle’ brother shrugged. He stole the piece of meat in Luffy’s hand without looking away from the book, ignoring the younger’s protest, “I think basically, Alphas are the strongest, Betas are pretty normal and Omegas are weak,”

 

Now that Ace can understand. With a grin on his face, he leapt up to his feet, proudly pointing to himself, “I bet i’m an Alpha,”

 

“How so?”

 

“Cuz i’m the strongest one out of you guys,” 

 

“Hey, that’s not fair! I can be stronger if i’m bigger than you,”

 

“Well, Luffy, maybe you’re an Omega, because you’re small and weak,”

 

“No way! I don’t want to be an Omega, I wanna be an Alpha!”

 

“You guys do realize that we won’t know if its true or not until we found out, right?”

 

“Boo, Sabo, you’re such a Beta,”

 

“Why are you making that into an insult?!”

 

Their squabble that night was stopped when Dadan climbed up and beat the hell out of the three of them, shouting at them to ‘shut the hell up, people are trying to sleep!’. The discussion was promptly forgotten the moment they woke up, and they never mentioned about it ever again.

 

(Then of course, Sabo died, and Ace left to begin his journey. Nothing else mattered aside from that.)

 

* * *

 

According to the schedule posted in the main area, the Whitebeard Pirates were only supposed to land for supply run. Yet when Ace arrived this morning, an additional note - with Marco’s familiar handwriting - made it clear that they will be staying in this island until further notice and a new schedule has been made for each division.

 

Changes in schedule happens from time to time, but this one made him quite curious. Usually, changes were made due to emergency or accidents, such as when someone was fatally injured or if there’s an unforeseen circumstances with the weather that forces them to lay low. But the weather outside was great for Grand Line’s standard, and there hasn’t been in any kind of fight recently. Yet, ‘until further notice’ could mean from a few days to weeks, and that means something serious must’ve happened.

 

He asked about it during breakfast, in between trying to shove a buttered bread and a spoonful of rice pudding into his mouth.

 

“Oh, you haven’t heard?” Vista answered, taking a sip of his morning tea, “It was one of the men in Fossa’s division. We’ve been running low on suppressant because of the marine attack two islands ago, and the last island we stopped by didn’t have them on stock. Poor guy was close to his heat and it hits before we could get any more. Didn’t you hear the ruckus yesterday in his workshop?”

 

As a matter of fact, Ace had. But the moment he heard everybody rushing out from the lower deck, his narcolepsy hits and he woke up on the deck with a blue scarf pillowed underneath his head.

 

Which reminds him, he hadn’t quite returned it to the owner yet. He had it in his pocket since yesterday, but evidently the older man is busy, since they haven’t even crossed path since.

 

Oh well, he’ll look for Marco later.

 

Instead, he focused on the matter at hand, “What’s a suppressant?” And why does he even need it in the first place?

 

The top hat wearing man blinked at him, his mouth opening and closing as if he wasn’t sure what to quite say, “Well, its for his heat, Ace. Surely you know what that is?”

 

“What, like the weather? You mean like a heatstroke or something?” It wasn’t that hot outside, is it? _Mera-mera no mi_ might’ve skewed his sense of temperature a little, but even he would’ve noticed something.

 

It didn’t seem to occur to Vista that he had dropped his steaming cup of tea, but Curiel, who sat right next to him, realized it and screamed bloody murder when the piping hot beverage started dripping to his lap, “Vista, what the hell?! Somebody get me a clean towel, i just washed these yesterday!”

 

“Ace,” instead of addressing the shoutings and curses behind him, Vista grabbed the second division commander by his shoulders, pulling Ace away from a chunk of meat, “Please tell me you actually know what secondary genders are,”

 

The term sounds quite familiar, but it took him a while - since he was rather irritated from being pulled away from his favorite food - until a quick flashback of the events that happen in the treehouse passed through his mind. He nodded, snatching the elusive meat, “Yeah, i remember it. Alpha, Beta and Omega, wasn’t it? What about them?”

 

“What about them— Ace, do you even know how secondary genders works?”

 

If he had known that his curiosity about the schedule change would cause him to be disturbed while eating, he would’ve kept his questions to himself. The raven haired man pursed his lips, trying to remember what Sabo and the book told him, “Uh, i think it was something like Alpha is the strongest, Beta is kinda common and Omega is weak, or something? I don’t know, that’s all i can remember. What does that have to do with getting a heatstroke?”

 

By this time, Ace was aware that most of the commanders - sans Curiel, who is still fussing over his stained pants and Marco, who is not there - and half of the dining room was looking at him with strange expression on their faces. He pouted slightly, pretty used to being stared at but not when he doesn’t even know what he did to warrant such attention, “What?” The entire room was silent now, only filled with whispers from one wide eyed pirate to their confused colleague, and it continues on until virtually everyone was staring at him. Ace began to squirm under the table, unsure about what just happened.

 

Suddenly, the door was opened and Marco strolled in, the day’s newspaper in one hand and what was probably his old cup of coffee from the night before in the other. Ace watched him stopped short, noting the silence and looked around with uncertainty, “What’s… going on?”

 

Before Ace can say anything, Thatch, sitting on the very end of the same table he occupied, shouted, “Ace doesn’t know what secondary genders are,”

 

“Hey, i do know them!”

 

“He doesn’t know what heats are,”

 

“That’s why i’m asking! Is it not heatstrokes?!”

 

“Oh my god, what if he hasn’t even presented yet?”

 

“Present what?”

 

“D-did we took in an underaged child into the crew?”

 

“Who says that! You wanna take this outside, asshole?!”

 

A hand gripped his shoulder, stifling the fire that began to ignite around his arm. Ace looked up to see Marco right behind him, looking down at him with an unnerving gaze, “Ace,” the first division commander asked, voice strangely low, “Is this true?”

 

“Well,” he began, looking around but only seeing the same incredulous expression. Is it really that bad if he doesn’t know it? “Kinda?”

 

The grip on his shoulder became tighter, and a sense of foreboding entered the pit of Ace’s stomach. Could it be that it was some sort of an essential knowledge for pirates? None of his old crew member in the Spade Pirates ever mention anything, but then again, he had been their captain so maybe they expected him to know. Maybe anyone who didn’t know won’t be considered a real pirate or worse, would be immediately booted out from the crew. 

 

Would they really do that? He knew he shouldn’t have opened his big mouth. Oh god, why now, when he finally met a crew that he could call his family—

 

“Okay,”

 

“Huh?”

 

The hand suddenly disappeared from his shoulder and when Ace blinked, Marco was already seated next to him, newspaper neatly placed on the table. The older man began to read on of the top article, his head propped up by one of his hand.

 

Ace blinked once, twice, and was still left plain confused. Judging by the silence around him, so is everybody else, “Um, Mar—“

 

“There’s a lot of things in the world we don’t know, no matter how common it seems. Not knowing something is normal, no need to feel guilty or shocked by it,” with a lazy smile, he glanced at Ace. Something about that smile made Ace’s face grew hot, “Of course, just because you don’t know something doesn’t mean you can’t ask. You can, there’s plenty of us here you can choose from,” he paused, like there’s an afterthought, and chuckled warmly, “Or don’t ask, that’s also up to you. You might not want to know the answer,”

 

He sounded so cryptic, but at least everyone stopped staring and the ruckus raised once more in the dining room. Most of the conversations’ topic was surrounding him, but he had spent too much time talking and not enough time eating.

 

When he opened his eyes, he had his head on a plate of chicken and there are less people in dining area than before. Marco was also nowhere to be found, other than his newspaper.

 

Damn, he forgot to return the scarf.

 

* * *

 

“—makes you wonder how he missed the changes in his body. Think he really hasn’t presented yet?”

 

Ace was making his way to the deck when he overheard the whispered conversation from one of the storage rooms. He didn’t make it a habit out of listening in to other people’s conversation - he left that up to Izou and Haruta, who will share the gossip to anyone at all - but it was that word again that makes him stop. Besides, it didn’t take a genius to realize that the crew members were talking about Ace, and he’s always interested to hear what people had to say about him behind his back.

 

He spotted the offenders as two people from Atmos’ division, who were responsible to for cleaning out the food storage this week. Only one of them was working however, as the other was more interested in leaning against his mop and coaxing his friend to talk, “He could be a beta,” the disinterested one answered, scrubbing along the walls, “If he was really that ignorant about the biology of secondary genders, he probably dismissed his presenting as a normal fever. He’d know for sure if it’s an alpha’s rut or an omega’s heat. Everyone here’s using suppressant anyway, its hard to tell which from which,”

 

“But we’ve been low on suppressant for the last couple of days so no one’s been using them. I talked to one of the guys from his division and he said he only realized it now but he couldn’t smell anything from Commander Ace. And he’s an Alpha, their sense of smell is second to none,”

 

“Think he’s a late bloomer then?” ‘hard-working’ finally looks away from the persistent stain he had been scrubbing, a frown on his scarred face, “I mean, not presenting yet at 18 wasn’t unheard off, he’s only late by a year or so. Though if his body waited any longer, i feel bad for him,”

 

“Why?” ‘lounging-guy’ asked, almost at the same time the thought popped in Ace’s head.

 

“I heard it from another pirate crew. Their captain finally presented as alpha at 21, and his rut was chaotic. He tore off the entire room, chased down every omega around, even the ones who are not in heat, it was a disaster. Apparently your body kind of built it up or something, and if you presented too long, its like a broken dam,”

 

‘Lounging-guy’ flinched, “Damn, thank god i’m a beta, i got nothing to build up,” he was silent for a few while, before speaking in a hush tone that Ace needs to strain to be able to hear him, “Hey, uh, aren’t most of the crew here Alphas?”

 

‘Not-so-hardworking-anymore’ guy raised a brow, his work has long since abandoned, “Yeah? What about it?”

 

“I don’t know, it might be kinda farfetched seeing how he is, but if what you said was true,” he looked around, and Ace made sure he was well hidden behind the door, “What if Commander Ace is an omega?”

 

The two were silent for such a long time that Ace had to peek from his hiding place to make sure they didn’t somehow disappear. But the two crew members were indeed inside, staring at each other with unreadable expressions. The silence was broken by ‘Back-to-hardwork’ guy, who silent turned back and began scrubbing the walls, “I don’t want to think about it, man,” ‘Lounging guy’ finally looked away as well, silently mopping the damp floor.

 

Ace remained there with his muddled thoughts in silence, and left before the two could even hear him.

 

* * *

 

The schedule has been updated once more. They’d stay in this island for a week, but there are possibilities that there might be another change.

 

Ace checked the patrol schedule for his division, and left for the island.

 

It was one of the more tropical island in Grand Line, a neutral area that was far enough from any marine headquarter that pirates can relax and take their time. Of course, by the time Moby Dick puts down their anchor, most of the smaller pirates has already left, as if Pops’ jolly roger had scared them away. Ace himself had never been to this particular island before, but he had heard rumours about it during his time as the captain of Spade Pirates.

 

Of all of the rumours he had heard, he wished there was something other than ‘relaxing hot bath and massage centre’ and more ‘places to study some biology thing you never cared to learn about but needed to know now’.

 

After wandering about the island - and narrowly being seen by a crew member - he finally settled with an old bookstore in the middle of the shopping centre.

 

It’s been so long since he actually had to sit down and read a book; the last time had been in the treehouse, when Sabo had the rare moments of determination to teach both him and Luffy how to actually read, all of them varying in success. He never found the patience to simply sit down and read small lines from a dusty old book, and right now, he found less patience still trying to find the correct section for the book he was searching for. After rounding another section, the old man from behind the counter began following his every movement with suspicious eyes, so Ace ducked into one that says ‘Health’ and tries his luck.

 

Like every old bookstore he came across in every other island, this one was a mess of books, new and old, some with language and accent of a particular area in one of the 4 seas, rarely any of them from East Blue. Ace groaned at the large amount of books; It’ll take ages to go through each one of them, and he wasn’t even sure that the one he was looking for was actually available. 

 

Still, journey of a 1000 steps and all of that.

 

He was close scanning through the second row of books when he come across a familiar book spine, but as he pulled it out his eyes suddenly felt heavy, and Ace could feel his body slamming against the bookcase behind him before falling deep into slumber. He didn’t usually dream when he fell asleep from narcolepsy, but for some reason, he thought he could see flashes of a deep red and symbols he swore he had seen somewhere, as well as the image of a smiling blonde boy and a straw hat limply falling from a sleeping boy’s head.

 

Ace woke up lethargically, unwilling to leave the images behind. He was lying on his side, and there was something flimsy covering his upper body. For a moment, he thought the suspicious old man from behind the counter had found him asleep and decided to pity him, but there was a whiff of a familiar scent from whatever it is that was cover him, and it tells Ace that it wasn’t exactly the case.

 

When the bleariness left his eyes, the raven haired pirate saw a pair of legs in front of him, encased with familiar sandals with leather straps. He took in a deep breath - so that’s why the smell had been so familiar - and looked up to see a naked back, and a familiar tuft of blonde hair shaped like a particular fruit. 

 

He took another deep breath, and sat up, holding Marco’s purple shirt against his chest. It still felt warm from the sun outside, meaning that either he hadn’t been in here long or Ace’s current episode was pretty short, “What are you doing here?”

 

Marco didn’t look away from the thick tome he was reading, “I like looking around the bookstores of every island we come across,” he replied, his low timbre sending shivers to Ace’s still sleep clouded mind. Then, he gestured to the direction of the counter beyond the bookcase, “Though with this particular bookstore, i’m simply familiar with the owner and wished to visit,”

 

From between the books, Ace could see the old man waving cheerily to Marco, before settling back to a suspicious glare to Ace. 

 

Ace pouted at the differential treatment - though, to be fair, he did accidentally fell asleep in the guy’s store - and didn’t notice that the first division commander was staring at him until he looked up, “What?”

 

Marco’s eyes peered to his side, “Starting out from the basic. Clever,”

 

It took him a moment to understand what Marco was referring to, until he saw the book next to him. The cover was exactly how he remembered it to be all those years ago, with its garish red cover and the bold titles. The only thing that separated this book from the one in the raven’s memory had been the yellowing pages, and the fact that it didn’t faintly smell of spilled broth from one of Luffy’s antics.

 

Ace picked it up and fanned the pages on his lap. As expected from a book intended for children, the words were sparse and there were helpful illustration here and there to make absorbing the information much easier, “This was the book my caretaker gave to us after we prodded her long enough to explain,” he explained, stopping at a particular page full of diagrams, “It’s where i learn the whole thing from,”

 

The next page was full of words, instead of pictures and Ace bit his lower lips.

 

“Something the matter?”

 

When Ace looked up from the book, Marco had stooped down to his level, crouching in a way that was not unlike his usual phoenix stance, as if it was a force of habit. Even the way he cocked his head questioningly was a reminiscence of garden variety avians, and it wasn’t the first time Ace wondered if Marco himself realized his actions, “Not a problem per se,” he admitted after a while, pushing all sorts of comparison out of his mind, “It’s just that, last time, i had my brother to read this to me,”

 

The reminder of Sabo still hurts, even years later, but right now, the sting in his chest wasn’t simply based on that. This is not the first time he caught himself sharing a piece of his past to anyone who asked aboard Moby Dick, and though he has yet to reveal the biggest stain in said past, he’s pretty sure that by now, everyone has known so much about him. Yet, every little tidbit of his life that slipped past his lips always feels heavy, especially to the blonde man in front of him.

 

It’s probably because just from those little pieces, Marco always seems to look past him, figure out things beyond what he was willing to share. 

 

Just like right now. The blonde took one look at him and the book, before he spoke, “I could read it to you,” 

 

It seems simple, but at the same time, Ace knew that Marco worked out that it wasn’t only due to sentimentality, but that just like this entire secondary gender mess, reading was another thing others took as a common knowledge that he doesn’t. He’d blame his own stubbornness on this, but after Sabo died, nothing aside from training to get stronger and realize their dreams mattered. 

 

This wasn’t something he ever told anyone, not even back then with the Spade Pirates. Yet somehow, he knew Marco knew. Hence, the offer.

 

It’s unnerving, yet at the same time, Ace wondered why it was always Marco who he felt at ease in telling everything to.

 

Ace closed the book on his lap, nodding.

 

* * *

 

Commanders private quarters, as Ace found out, were a huge step up from the common quarters that everyone else had to share. Marco’s was an even higher upgrade, probably one of the bigger rooms aside from Pops’, though given his rank and responsibilities, that was probably a given. Like always, whenever he found himself in here, Ace’s eyes would drift from corner to corner, at the crates full of maps and log poses, stacks of documents, inks and quills, and even to the false bottom underneath the older man’s desk, where he kept some of the finest bottles of booze from all 4 seas.

 

One of said bottle was fished out as soon as they both entered, poured into two glasses that was held in each of their hands now. Ace fidgeted a little with his glass on the bed, trying to not to stare directly at Marco himself. The man had occupied the only chair before his desk, jacket slung on the back to reveal the entirety of Pops’ mark. With glasses on, one hand casually stirring his half drunk beverage and hand propped on his thigh as he peered down to Ace’s book, this is the most relaxed he would ever be, in the privacy of his own space.

 

Ace has it in good authority that not many people aside from himself has even seen Marco in this state. He liked knowing that. A lot.

 

His musing was finally broken by a small amused huff, “This really is a book for kids,” Marco said, peering from behind his glasses to smile at Ace. There’s a stutter in Ace’s stomach, which he tried to hide by taking a sip from his glass, “But they covered most of the basics. Are you following so far?”

 

To be honest, Marco’s soft timbre was long since lost from Ace around the third page or so, and he’s pretty sure that they had gone through plenty more pages since. He’s pretty sure that Marco himself knew it too, because there’s an amused lilt on his question and his smile grew a little when Ace stammered out his reply, “K-kinda,”

 

Marco’s smile grew larger, just as Ace’s face grew hotter. 

 

In an attempt to divert the older man’s attention from this, Ace blurted out, “What am i?”

 

The blonde quirked a brow, “Pardon?”

 

“I mean, which one of those am i? I wanted to find out, that’s why i searched for that book,”

 

This question brought Marco to a pause, in which he slowly crossed his arms and leaned back to his chair, “Well, to be honest, i can’t really tell you,”

 

“Why not?”

 

“Because i can’t sense anything. I thought you’ve just been using a lot of suppressants,”

 

Well, he doesn’t even know a thing called suppressant existed until yesterday. Ace looked down on himself, remembering what the conversation between the two crew members yesterday, “So, could it be that i really hasn’t presented, even though i’m over 18?”

 

At his words, Marco quirked a brow, looking down on the book and back to Ace. He seems contemplative for a moment, lips slightly parted, “It’s not a bad thing,” he said slowly, eyes boring to Ace’s own. He seems quite tense for some reason, lips pressed tightly as he continue to speak, “I can assure you that there are other cases such as yours, if that is truly what happened. You don’t have to worry about it,”

 

Ace nodded, if slightly confused by the slight change in Marco’s tone, “Yeah, i know. I heard the guys said something like that,”

 

Once he said that, the first division commander visibly relaxes, the easy smile back on his face. Ace didn’t know what he said to make such changes. Instead, he changed the subject yet again, “What about you?”

 

“What about me?”

 

“What are you then?”

 

The smile was back on the older’s lips as he pointed to one of the symbols adorning the book’s cover. Ace might’ve lost him a couple of pages later, but he had been paying full focus when Marco started off with the initial introduction on this entire subject, including what the symbols on the cover meant, “Huh,” he hummed, more to himself than anything, “Guess it makes sense that you’re an alpha,”

 

“Oh?”

 

“The guys yesterday said that a lot of people on this ship is one,” he paused briefly, distantly remembering the very few things he remembered Sabo had read off from that book years ago, “Also, if you’re big and strong, that means you’re an alpha, right? That’s why it makes sense,” At least, it does in Ace’s mind. But apparently, this assessment and reasoning might be wrong because Marco laughed, an honest and amused sound that may or may not have made Ace pout a little, “W-what, you said i had to guess!”

 

“I’m sorry, Ace, i’m not laughing at you,” the blonde said as he calmed down, taking a sip from his glass, “Then again, you did learn from a book for kids. A really old, outdated book for kids,”

 

That did little to reassure the raven, who starting glaring the more he felt his cheeks grew hot, “But it’s true, right?” he finally asked after Marco’s laughter died down, “That’s what i remembered from back then. Alphas are stronger, betas are just average and omegas are the weakest,” He remembered having fought Luffy about it, the desire to be strong that has been there since he was young, “Is that not how it worked?”

 

“The thing is, your secondary gender plays little role to how you’d look physically. They do give you some unique characteristic; Alphas usually have better senses, betas are normally pacifist and diplomats and Omegas are a lot more sensitive to their surroundings. In the world we live in, they played very little role in the grand scheme of things. It didn’t use to, but times has changed,”

 

Ace pursed his lips. He didn’t really get it, but this seems a lot more complicated than he thought it would be.

 

With a sigh, Marco placed the book on his desk before standing up and made his way to the bed. He took the empty spot next to Ace, his arm brushing against Ace’s own due to their closeness, and he placed said hand on top of Ace’s head, rubbing lightly, “You don’t have to worry about this sort of things. It’ll come naturally for everyone, including you,”

 

He didn’t really mean to, but Marco’s gesture was comforting and Ace found himself leaning against his touch even more. He heard the older chuckle before he realized what he was doing, “I think instead of worrying what you might be, you should be a bit more concerned about making sure you’re a logia and not a cat zoan or something,”

 

“Shut up, it felt nice,” he complained, his pout turning into a grin before he giggled when Marco’s hand left his head and goes under his chin instead to scratch it like one would a feline. He tried to squirm away but Marco followed him, causing the two of them to tumble on the older’s bed and the glass in his hand to fall onto the floor, thankfully not breaking but it was enough to make him jolt, “Oh shit, now look what happen—“

 

Pushing himself upward turns to be a mistake when Ace felt his cheek bumping against something soft and turned to see that Marco’s face was really close to his, so close he could smell the scent of sea, ink, and aftershave, with something rich underlying it all, something that he cannot describe as anything but simply tantalizing. He’s close enough to see the dark flecks in Marco’s blue eyes, to feel warm breath against his face and felt the undeniable heat of a body against his own naked skin.

 

Ace should move away, he knows, but at the same time, it felt like something was keeping him there. His limbs felt locked in place, his eyes couldn’t avert themselves away from the striking blue orbs looking down at him, and that scent, that unexplainable scent feels like it was lulling him, tugging him close. In that daze, Ace felt his lips parting and inhaling, hearing his own lips smacking and watering for no reason—

 

And then suddenly Marco was gone in a blink of eye.

 

“You should go,” he heard being said quite far away, and found that Marco had his face turned away, far enough that he knows it was done deliberately. He sounds like he was breathing heavily, and like he was in pain, “I’ll… i’ll read the book for you some other time, but i think you should go now,”

 

Ace didn’t understand this sudden change, and somewhere deep in his head, he already missed the closeness, “But—“

 

“Please, Ace,” the man begged now, and the desperation in his voice is startling, “Please, just… not now,”

 

He wanted to argue, wanted to say he didn’t know what he did to cause this change, but Marco turned to him partially, eyes pleading. And it felt like rejection right there, one that stabs Ace in his chest, so he stood up, took the book with him and left without another word.

 

He stayed outside of the door long enough to hear a low muffled moan from inside of Marco’s room, looked down to the book in his hand and felt like he had just missed something crucial.

 

* * *

 

He didn’t see Marco again that entire day, and it wasn’t until he returned back to his own room that night that he realized he still forgot to return the older man’s scarf.

 

Ace took it out of his pocket, fiddling with the fabric for a little as he tried and failed to understand a word from the book and held the scarf close to his face. It smelt exactly like before, with the same scent of sea and the rich undertones that tingled his senses. He closed his eyes as he sniffed it even more, and before he realized it, fell asleep still holding the scarf to his face.

 

He woke up the next day with that scent still on his nose, and with an unexplainable churning in his stomach. 

 

* * *

 

Everyone is looking at him.

 

It wasn’t something that should’ve missed his attention, but he’s feeling even more hungry than usual that morning so the sight of food had been incredibly distracting. It wasn’t until he was halfway down his mountain of food did Ace realized that everyone around him was staring at him, and with a mouthful of mashed potato, only hummed in confusion.

 

Izou was the first one to speak up, fan flared in front of the bottom half of his face and swaying rapidly, “Ace, um,” he started hesitantly, and if there is one thing the young raven thought he would ever see Izou be is hesitant, “Are you, um, are you feeling… different?”

 

Different? He gave a cursory glance at himself, “No? Why’d you ask? Do i look different or something?” Did he wear his pants backwards? Or not wear one at all? Won’t be the first time, but then, that one time had been an emergency. At the time, everyone had laughed at him - excluding Marco, who gave him his top to tie around his waist so he can keep a bit of modesty - instead of just staring wordlessly like this.

 

His stomach churned again, a bit harder than the last couple of times. He winced at the pain, “Actually, i think i had a stomachache or something. But at the same time, i felt really hungry, so this is kind of uncomfortable,”

 

Just as he said that, suddenly, the freckled male felt his stomach tightening again, almost making him double over at the intensity, and to make matters worse, felt trickling from between his legs and to his pants.

 

Next to him, Kingdew suddenly jumped away, eyes wide, and Haruta was suddenly behind him, both hands gripping on his shoulders and pulling him back, “Ace, we need to get you away from here,”

 

“Wait, wait, something’s wrong,” Ace said urgently, dropping the food in his hands to grip his cramping stomach. There’s goosebumps on his skin now, and he felt feverish, something he never thought he’d ever feel again after gaining _Mera-Mera no Mi_. The seat of his boxers felt wet with whatever it is he’s leaking out, and that made him even more reluctant to move away, “I— i don’t know what’s going on, what’s happening to me? What is this—“

 

From the corner of his eyes, he saw someone moving close before he heard the shouts, and suddenly Haruta was knocked back from behind him before he was pulled by brute force. Ace found himself staring face to face with Blenheim, whose eyes were blown wide, pupils unfocused and breathing heavily, “This is… i’ve never smelt one like this…. Fuck, your scent is amazing—“

 

Just as quick as he appears in Ace’s line of sight, the braided Commander was pushed away, this time by Vista and Rakuyo, “Blenheim, control yourself!” the top hat wearing commander grunted, but he looks no different than Blenheim himself in his wild expression, “Haruta, get Ace far away from here!”

 

The hands that tugged Ace again was Haruta, no doubt, but his vision has started to blur and his body began to heat up. When Haruta’s hand gripped his arm once more, Ace let out an involuntary moan, one that shocked him to his core. Why did that feel so good? Why is he getting even wetter? What is happening to him?

 

Someone lifted him up, someone who from the cool scaly sensation against his own skin he determined to be Namur, and in the midst of the shouting and chaos erupting around him, Ace’s consciousness slipped away.

 

* * *

 

“It’s called a heat, Ace,” Haruta’s muffled voice sounded from outside of the door, “You’re in heat,”

 

Ace could barely hear him, not when all he could hear right now was ringing and the only sensation he felt was arousal. As soon as Namur tossed him to his bed and left, he took of his clothes, feeling even just a hint of fabric against his skin to be irritable, and realized that the trickling he had been feeling all the time was caused by an unexpected erection and something else dripping out from the back.

 

He had touched himself, trying to take care of it the way he knew how to, but even after he came with what felt like the most explosive and body-wrecking orgasm he ever had, he still found himself hard and soon, it felt like it wasn’t enough.

 

“What am i supposed to do?” Ace mewled out, almost sobbing because his dick felt raw and his ass is throbbing. He knew of things that can be done back there - living in a pirate ship with so many people kind of teaches you some things - but the concept of it was weird, and he can’t bring himself to even reach. Yet at the same time, he felt the need to.

 

Haruta doesn’t answer, and there is no way for Ace to know if he’s even still out there. The dark haired male moaned again when he felt even more wetness dripping from him, trickling down his sensitive balls and made him feel even more mortified than before. His front arms gave out, and he let himself fall down to the bed, both knees still propped up and ass exposed to the air. He felt so vulnerable like this, despite being all alone, and he hated this.

 

In the midst of oversensitiveness, he caught a whiff of a scent, and lifted his head to find that his head has landed quite near where he had tossed Marco’s scarf this morning. It was just as pronounced as yesterday, if not stronger, and without thinking, Ace pulled it close, burying his face into it.

 

And just like that, everything felt both worse and better. Better, because Marco’s scent lull him again, calming him slightly and washing him with relief, as if this was what he’s been looking for. He buried his nose even more to the fabric, taking it all in and not even registering the small moans that he made and how he had began to drool over it.

 

Because right now, he felt even more on fire. His body is moving on its own, pelvis grinding down to the sheets to find some release and his sphincter muscle quivering in unexplained anticipation. He’s hard again, after coming only a while ago, so with a reluctant sob, Ace extended one hand behind him and reached to his rear. His crack was sticky with slippery liquid now, one that made him squirm in contact and the closer he traced up to his hole, the more there are.

 

The moment the tip of his fingers touched the rim, Ace let out a moan that he would’ve been mortified with any other time, but he was too far gone. He whimpered as he breached the hardly protesting muscles, feeling his finger swallowed in a tight passage, and as he kept pushing in, the more it felt good, so, so good.

 

Ace’s legs were barely supporting him now, with how hard they shook, and the moment he bended his knees down a little, he could feel pre-cum staining his thighs, making his skin even stickier. He could care less now, pushing in two fingers into himself and when he moaned, it wasn’t quite wordless as it was a name from his lips.

 

The door suddenly burst open, and Ace lifted his head in shock.

 

On his door was Marco, as if he had been summoned by Ace’s utterance of his name, barely held back by Haruta and Namur. ‘Feral’ was an understatement on how he looked, teeth gnashing and eyes staring at Ace with so much want and lust that the young man felt his inside churning and his legs quiver.

 

“Fuck! Knock him out, Namur!” Haruta exclaimed in the frenzy, barely able to keep the older man out, “How the hell did he get here so fast?! He wasn’t even in the dining room!”

 

“Marco, snap out of it! It’s not just some omega in heat, it’s Ace! Our Ace!”

 

For a brief moment, Marco seems to gain some of his senses back, dazed eyes clearing up, before he actually _snarled_ and began to advance, despite Haruta and Namur’s best attempt to pull him back outside.

 

Marco’s arrival had blown the overwhelming scent that drove Ace deeper into this heat even worse, and seeing him getting closer made Ace’s stomach tightened itself once more. Still in all fours and with two fingers inside of himself, Ace felt like he was barely in control of his own actions as he mewled out, “Alpha?”

 

Marco’s eyes widened even more, his breathing turning hot and heavy.

 

“Ace, no! You’re not yourself, right now, and he’s— fuck, Namur, pull him out of here!”

 

“I’m trying! Marco’s— just— fucking— strong— Gah!”

 

With one sharp tug, Marco managed to get his arm out of Namur’s grip, turning said limb into blue fiery wings that knocked the fishman out of the room completely. Startled by the attack, Haruta’s own grip turned lax, and in that split second, he was also hit by Marco’s wings, sending him stumbling out of the room. As the two laid daze on the floor, Marco closed the door and locked it, ignoring the repeated banging and shouts.

 

“Omega…,” he panted, and his voice was so foreign Ace wouldn’t have been able to recognize him if it wasn’t for the unmistakable overwhelming scent, “Ace, Ace…,”

 

Just from hearing his own name in that voice made Ace tremble, his hole dripping wetly against his fingers and knuckles. His insides are pulsing with want, and the closer Marco gets, the stronger that scent becomes, Ace found himself drowned in it, “Alpha,” he whimpered, clutching his sheets tightly as he drive his fingers deeper into himself and watched Marco’s eyes grew even darker and staring at him unblinking, “Alpha, Marco, please,”

 

He doesn’t even know what he wanted from Marco and what he was begging for, but Ace knew he needed it badly. So he doesn’t fight it when Marco finally climbed onto his bed, and he doesn’t fight it when Marco descended on him.

 

What happened next was a blur of motions, a flurry of kisses and hands on his skin, touches that made him melt and the growling voice in his ears that made him weak everywhere. Marco buried his nose on his neck and his fingers inside of him, driving Ace insane with his motion, mouth lapping on his chest and sensitive nipple as his other hand played with his cock, teasing the leaking head gently once second and harshly tugging on it the next.

 

Ace felt like a mess, his whispers and whimper turning into screaming and moaning on top of his lungs, and he was sure he already ripped his bedding after Marco put in a third finger into his hole, stretching him even more and jamming them in with a brutal but pleasurable speed. The spot underneath his ass was damp, from sweat or his numerous leaks, Ace couldn’t tell anymore, but he didn’t have to worry about it when Marco turned him again to his front, putting him back on all fours.

 

Tears now made their way down his cheeks instead of the corner of his eyes, and he felt the heat of Marco’s body before the man was looming over his back, nose nudging on his ear before he felt feathery kisses running along the shell and down his shoulders, “Mine,” Ace heard Marco hissed, and suddenly, the fingers inside of him was pulled out with a lewd ‘pop’, making him whine in dissatisfaction, “Mine, my Omega, my mate, my Ace,”

 

With Marco so close, his scent and never ending pleasure fogging his brain, Ace didn’t even realize as he unintelligibly and near incomprehensibly babbled, “Yours, Alpha, yours, please Alpha, Marco, please,”

 

Marco snarled to his ears, the sound sending tremors down his spine, “Mine,”

 

Suddenly, something much larger than the fingers, much harder and wide was shoved into his hole and Ace _wailed._

 

It felt so good, it felt satisfying, unlike his fingers and his jerk offs, he felt so complete. He felt his own muscles spasm around it, making Marco moan and hiss, as he felt hand gripping tightly on to his waist in a bruising grip. Ace didn’t mind, not when that grip is used to keep him still as Marco drew back just enough before slamming into him hard.

 

Ace sees nothing but stars and dark coloured dots before his vision.

 

The noises he made led him to believe that he looked absolutely shameless right now, but Ace couldn’t bring himself to care. He cried out Marco’s name to high heavens, only once in a while intercepted with ‘Alpha’ and ‘please’, hands clutching on his sheet and ripping them because of the intensity of his pleasure. He came only after being driven in 3 times, and after another 3 bed-rocking slams, Ace was hard again, crying and sobbing over the intensity of his come and the over stimulation to his insides.

 

But conflicting to the harsh rocking of his body and the violent thrust to his quivering wet entrance, Ace could still feel soft kisses to his back, shoulders and ears, hearing his name being whispered and moaned out so deliciously as the blonde peppered kisses and even gave little licks to a particular spot behind his nape. Barely anything Marco said aside from his name made any sense in the daze of his pleasure, but he caught words like ‘mate’ being repeated over and over, and the promise to ‘make everyone else know that Ace is his’. 

 

“Make me yours,” the dark haired, tired male bleat, eyes rolling back to his head at a particularly hard thrust, “I want to be yours, only yours, Marco. And you’re mine,”

 

The thrusting stuttered, losing its momentum as if caught off guard. Ace sobbed again, already on the edge of another completion, and he felt a hand cupping his jaw and tilting it to the side. The older man leaned closer and pressed a soft kiss to his lips, the gentlest gesture he had been given since the moment he entered the room.

 

Marco pulled back slightly, and in that moment, Ace found his eyes, half hidden behind limp and sweaty blonde locks, glazed over with lust and desire, but also something else akin to affection, “I’ve been yours all this time,” he whispered, before connecting their lips once more.

 

Their lips were still connected to the kiss as Marco plowed into him a couple more time, until Ace came with a weak moan, and he felt the older pulled out, and there's drenching wetness staining the back of his thighs and ass. He could tell that it was Marco coming, from the strangled groan that came from behind him.

 

Ace flopped down to the bed, and still panting heavily, he felt Marco nudging on his shoulder again, kissing down the same particular spot on the back of his neck as he has been doing before. 

 

He waited for Marco to do anything else, but the man pulled away, almost hesitantly. 

 

Ace never had the chance to ask why when he finally succumbed to his fatigue and fell into a deep slumber. 

 


	2. Part 2

**Notes for the Chapter:**

> WARNING: Even more smut than before, A/B/O tropes used in smut may cause deviation from how normal sex works, mentions of the possibility of Mpreg, but no real payoff (maybe not here, because i know it’s not everyone’s cup of tea), and smut. Did i mention smut?
> 
> I assumed that everyone reading already knows about A/B/O universe and the comments proved me otherwise, so i’m sorry about that oversight. I tried to explain it a bit more in story (well, at least, how it work here. A/B/O rules mostly works how the author wants it so mine may be different from others) so i hope that will minimized any confusion. 
> 
> Hope you'd enjoy!

 

“Stop, stop this, please…,”

 

It was to that begging voice that Ace finally come to, eyes heavy and body inexplicably sore all over. He’s no longer lying to his front but to his back, with hands on both sides of his head and lower half numb. At least, he thought it was numb when he could barely felt anything, but the sensation slowly returned like rushing blood, and he could feel before seeing one of his legs raised by a strong hand grip and the other propped against another body between them.

 

The voice returned, sounding like it was in pain, and it was with alarm that Ace opened his eyes further. Instead of finding anything remotely dangerous, however, he found Marco in between his splayed legs, one hand lifting his leg by the back of the knee and the other covering his face.

 

His face, and eyes that looks _terrified._

 

Ace wanted to call out to him, yet his throat felt hoarse and dry. Marco hissed, eyes squeezed shut, removing the hand away from his face to slam it to the wall next to them. The sound of impact would’ve made Ace jump, if his entire body didn’t feel like wet noodle. 

 

Still, in this current pose, Ace could see something else of Marco’s that had been covered before by his hunched posture. He was raging hard, cock erect and seems almost painfully red even as it leaked out pre-cum, and there was an odd swell by the base that he can see was pulsing weakly. The blonde was staring at it with near contempt, as if hating whatever it is that’s happening between his legs.

 

Staring at the commander’s cock sends jolts of want into Ace’s core, and as he had expected would happen, he felt his hole growing wet once more, making him groan at the wispy and tingling pleasure the sent to his nerves.

 

Marco obviously did not expect him to be awake because he gasped at the noise, “Ace,” he breathed, voice shaky, nothing like the confident and dominating presence he was before.

 

But even then, Ace felt him self growing feverish by just hearing his name uttered in that low, intimate voice. On instinct, he moved his free leg closer to Marco’s side, his knee knocking against the man’s ribcage and his ass wiggling slightly on the bed, crawling a little closer to the older’s pulsing organ, “I— i need…,” he moaned, his body knowing what it wanted since he woke up and his mind only now catching up with it, “I need you, Alpha,”

 

“Stop,” Marco growled lowly, his tone urgent and dangerous, but instead of it halting Ace in any way, his voice only made the dark haired male shiver, “Ace, i’m not… I’m not your Alpha. This is… fuck, how did i let this happen…,”

 

He sounded absolutely upset, and the rejection stings, both deep in the younger’s chest and more physically inside of his core. Ace mewled pathetically, unsure as to why there’s an uncomfortable tingle inside of him but knows he needs to get rid of him, and that he needs Marco, and that he’d beg if he needs to, “Please, Alpha. I need you, please…,”

 

The blonde’s chest was heaving slowly but heavily, as if he was deeply focused and holding back. The lust and desire in his eyes are undeniable, burning so intensely Ace could feel himself getting hard again when those blue orbs trailed down his body, while his dick began to leak even more precum, so hard it was bobbing with the slightest intake of breath. And yet despite all the telltale sign of want, he didn’t do anything, only breathing even heavier and louder.

 

“Ace,” he finally said, voice strained, “You don’t… you don’t know. You don’t know what you mean. You’re in heat, your first heat, you’re not in control. I’m not your Alpha, and you’re nobody’s Omega. You don’t really want this,”

 

But he does, he does know he wanted Marco, wanted that pulsing, flushed cock inside of him again, stretching his walls and filling him so completely. He wanted Marco behind him, on top of him, inside of him, he wanted that scent to envelope him again, drowning him in it and be devoured by it. So Ace lifted the leg still in Marco’s hold and hooked it on his shoulder, while he let his other leg trap the older by his waist as much as he can.

 

His hole is getting so wet, dripping down to the bedding, now that it’s so close to that large organ, so close he could feel the raw heat.

 

“I do,” the freckled male sobbed, wishing for that release and pleasure once more, his body burning in a way that not even his flame could ever achieve, “I want you. Please, Marco,”

 

He sighed the name with so much want, pouring his entire desire in it, and he knew it worked the moment the older’s eyes grew dark and mouth gone slack. The hand behind his knee started sliding down, down to his upper thigh and finally between his legs, and Ace could’ve cried out when those fingers grazed his leaking entrance. It felt so good, so close, and he needed it like he needed air.

 

“I need you,”

 

His hole was once again filled and stretched open in a single thrust, and a scream was torn out of Ace’s throat.

 

* * *

 

When he opened his eyes next, Ace noticed that he’s lying on his side and covered in sheet, the cool linen both feels heavenly and uncomfortable on his skin. His stomach was no longer curling and he could think a bit more clearly now. Enough to assess what just happened to him.

 

He had his heat.

 

He’s an Omega.

 

Younger him would’ve been furious to know with how much he had wanted to be a big strong Alpha, but right now, Ace didn’t know what to think. The heat made him feel vulnerable for a moment, confused and scared with the changes in his body, but right now, he barely felt anything. The only other sensation he remembered from the long, confusing blur had been the absolute pleasure, one that shook him to the core and now left him slightly empty. 

 

And that scent, that still lingering scent.

 

He opened his eyes further, to find a smooth, pale back facing him.

 

Marco’s shoulder was taut and his muscles tense, with his head buried in his hands. His entire pose screams misery, and while his scent was still there, it wasn’t boldly flaring all around the room anymore, just mild enough for Ace to know he’s there. 

 

Ace shifted his legs and grimaced. His legs felt sore, but it’s nothing compared to his hips and ass, aching in a different way than it had been before. To add to it, he could feel something thick and gooey dripping out from him, trickling down underneath the globe of his rear and making him shudder when it kept running down. He shifted his leg again just to stop the dripping, trying to sit up before a jolt of pain reminds him that his lower half was not in the best of state.

 

He was too preoccupied, that he briefly forgot about Marco, until the dark haired commander looked up and saw the man staring sideways at him. He looks anxious, almost hesitant in meeting Ace’s eyes, which was unlike the Marco Ace knew. 

 

“Some of it spilled,” the blonde said quietly, “But i promise i didn’t knot you. And with you on your back, i can’t bite your glands,”

 

Ace think he was supposed to have an opinion on that, maybe something like relief, because Marco sounded like he was trying to comfort him. But all he felt was confusion, as he made it clear to the man, “What are you talking about?”

 

Marco winced, as if Ace’s words somehow wounded him further, “You… right. You didn’t know,” he doesn’t sound like he was addressing Ace at all, and he turned away, bitterly spatting, “Fuck, not like this. Not like this,”

 

His act, and remembering how hesitant he had been earlier made Ace nervous, stomach coiling in a different way than this ‘heat’ felt. The younger wanted to reach for him, to ask what was wrong, but as soon as he moved again, the cramp on his hips was back, and he could only moan lowly in pain, curling into himself reflexively. 

 

The bed creaked, and Ace looked up to see Marco moving to sit closer, but not close enough for him to be on an easy reach. He looked guilty and rather stricken even, eyes staring at Ace’s torso and lower, “I’m sorry. I shouldn’t have…,” he bit his lower lips, and took a deep breath before continuing, “Similar to how Omegas have heats, us Alphas, we…,” again he paused, and finally twisted his body enough to allow Ace to get a better look of him. 

 

Just like before, his dick was rock hard again, and the swell on the base seems to have grown larger, veiny and angry. Ace stared at it in amazement, and partially pitied Marco because surely, that has to hurt, “Alphas have ruts. Omegas in heats wanted to be knotted, and Alphas formed knots which can only be satisfied by, well, knotting an Omega and coming inside them. And in that situation, both Alpha and Omega will want to mate with their partner, a bond that can only be formed by the Alpha biting the Omega’s gland in the middle of intercourse,”

 

Despite himself, Marco chuckled, though it sounded painfully stale, “Guess i did ended up teaching you all you need to know, didn’t i?”

 

And despite himself, despite his confusion, Ace found himself replying, “You don’t sound too happy with that,”

 

Just like that, the ironic smile on the blonde’s face disappeared, replaced by an angry grimace, “How could i? Ace, if only you know what a horrible thing i had done to you— A heat and a rut should’ve been done by consenting parties. Not like… not like this,” he squeezed his eyes shut, lips pulled to a downward arc as he looked away, as if ashamed, “But yesterday, i caught a whiff of your scent, and somehow, my rut was triggered much earlier than it should. And when i smelled it again this morning, all over the ship, i knew you’ve finally presented. I shouldn’t have— I should have restrain myself better but my instinct took over too strong, like never before,”

 

Marco hung his head low, eyes still squeezed shut and sweaty bangs falling down to partially hide them. Down between his legs, he was still fully erect, pulsing and begging, and it was such a ridiculous contrast between the sombre mood the man’s expression gave and his obvious primal needs.

 

And it because he realized that, Ace started crawling over, ignoring the twinge of his muscles until he was close enough next to Marco. He placed a hand gingerly on top of the older’s thigh, trailing over slightly paler skin until he could brush the blonde’s navel and across equally blonde curled and coarse hair that decorated the very base of the flushed cock. Tentatively, he reached over, brushing lightly before his wandering hand was caught with a harsh pull.

 

“Ace, didn’t you hear what i just said?! You didn’t want this! You’re going to regret this once you’re out of your heat!” the first division commander berated him in frustration, “Look, Haruta and Izou should be here any moment, okay? They’re Betas, so they’ll be fine around an Omega in heat, and they’ll make sure no one gets in and did what i did. I’m going to leave while—“

 

“Do you regret it?”

 

His question halts the man mid-sentence, droopy eyes widening he wasn’t expecting Ace’s question. He quickly gained his composure back, expression pinched and troubled, “Yes, Ace, i do. I really do. I don’t want to hurt you, much less manipulate you during your first heat of all times, and i wish i could’ve take it all back—“

 

Ace crawled even closer, up to his lap, and despite all of his words, Marco was silenced, eyes glazed as he kept staring with so much obvious want. His breath even hitched when Ace placed his hand on his chest, and from his periphery, the younger could see his body reacting accordingly as precum began to leak out of his very obvious arousal, “Do you regret that it’s me?”

 

Just like the moment he entered this room, any cloudiness in Marco’s orbs disappeared, but only briefly. His voice was shaky, overflowing with longing that he kept refusing himself that Ace pities him a little, “I… That’s not… the problem…,” the older hiccuped, and as his breath began to stutter, his scent started letting itself known again, a lot more heady and thick in the air. 

 

Ace felt it wrapped around him, pulling him in, telling him Marco’s real answer better than Marco himself ever could.

 

“Because i don’t, Marco,” he whispered, the air from his mouth blowing hot between their naked skins. Marco’s chest trembled underneath his palm, a valiant display of restraint, and it was Ace’s duty to break him out of it, “I don’t regret that it’s you,”

 

A pair of strong hands gripped his hips, neither pulling or pushing away, but held on to him so hard Ace winced at the intensity and the pressure it placed on his aching muscles, “Stop it, Ace, i’m trying so hard not to— You’re in heat, any Alpha would be enticing to you—“

 

Having enough of Marco’s seemingly never ending protest, Ace bended down and kissed him hard.

 

The muffled protest against his mouth soon disappeared, while the grip on his hips slowly loosening. Ace pushed himself to crawl above Marco’s lap, and lowering himself just enough so his navel and stomach brushed against the hard knot. Marco moaned at the contact, the sound swallowed in full enjoyment by the younger before he separate them with a wet pop. With glazed eyes, Ace watched the redness that slowly crawled onto Marco’s cheeks, watching his defenses falls apart with a strangled moan as he brought their body even closer.

 

“I am thinking straight now,” he breathed, slowly feeling the churning in his stomach for what it is, “And i know it won’t just be any Alpha. I don’t want anyone else,”

 

The desperate look on Marco’s face crumbled even further, and when it was him who brought their lips together in another bruising kiss, Ace knew he had won.

 

“You barely knew anything about this,” Marco muttered to his lips, before once again devouring it in a searing kiss that sent tremors down Ace’s spine. The hands were back on his hips, their grip softer but much more adventurous, kneading daringly on the flesh of Ace’s rear yet almost shyly reaching more. Ace jolted his hips backward to that teasing finger, having it grazed against his abused entrance and moaned at the contact. 

 

The younger paused their kiss to let out a breathy moan, when a finger made its way inside of him, pushing against the wall carefully and slowly. He’s not leaking like he was before, since Marco’s finger came out only slightly damp from the residue of their previous lovemaking that leaked out of him earlier, and concluded that Marco is correct.

 

So with a bite to the older’s lower lips, he stared up to his eyes, to those fogged blue orbs that stares deeply into his own, “Then teach me,”

 

Just like that, he was laid back down to the bed, cradled gently unlike the push he had been expecting, with Marco looming over him. Ace reached up, framing the man’s face with his hands, slowly guiding it down to his own for a gentle kiss. He let Marco sat on the bed, in between his legs, let him soothingly run a hand up and down his leg and humped against navel and the side of his own limp cock, which slowly grew to life from the friction and the kiss. The older reached down, and just as Ace thought he was going to direct his painful erection inside of him, Marco only goes to wrap both of their dicks in his hand, effectively rubbing them together with his thrust.

 

“Put it in me,” he moaned in between their kiss, as Marco panted though his continuous thrusting motion. It felt good on its own right, but he had seen the state Marco’s arousal was in, and Ace highly doubt dry humping and jerking would be enough for him, “You said you needed to knot in an Omega. Just put it in and come inside me, Marco,”

 

But instead of complying, Marco shook his head, sweaty golden tresses flowing according to the motion and tickling Ace’s cheek, “Your heat is in remission right now, that’s why your mind’s clear. Out of heat, you won’t be producing slick to help with insertion and,” he paused, almost sounding embarrassed with what he said next, “It’s… it’s big, Ace. Knots are big, and there will be a lot of cum. I don’t want to hurt you,”

 

Ace wanted to protest, remembering how good it had felt inside of him and sure that it won’t hurt him, but Marco didn’t seem willing to budge about this topic, “Then do it when my heat comes around again. I can take it,”

 

Marco raised his head, enough for Ace to see that his eyes became glazed with desire just from his words, though his words, as Ace had witness in the last couple of minutes, continues to betray what he obviously want, “It’s not about whether you can take it,” his voice hitched mid sentence, hips stuttering mid thrust and he let out a short gasp. Ace arched up at the sensation as well, already feeling himself close to the edge of orgasm.

 

The younger came first, letting out a keening noise as heated liquid sputtered and pooled on his stomach. The older man was still panting above him, groaning with every last pump of his hand before he too finally reached orgasm, and the onslaught of wetness on his stomach and even chest made Ace gasp. 

 

The two of them were left panting, Ace laying weakly on the bed in post-coital bliss while Marco trying his best to prop himself up and from falling down on top of him. After a few more moments, he bended down to the side of the bed and grabbed something off from the floor, which turns out to be a wrung and stained towel Ace knew came from somewhere in his dresser. Evidently, it has been used before to clean him up, because he could see some white stains on the dark coloured fabric, crusting the threads.

 

As he cleaned in silence, Marco finally spoke up again, sounding a little hesitant, “An Omega’s heat signals that they’re at the height of their fertility, and finally presenting mean you are ready to bear,” he trailed off, eyes pointedly looking away from Ace’s own, “And though it wasn’t quite as common as females, it can also happen to male Omegas,”

 

The towel was thrown away, once the blonde seems to deem them both relatively clean and he sat back, eyes trailing towards Ace’s abdomen with one of his hand rubbing the side of the dark haired male’s hips, “An Alpha’s rut happen when they’re on their peak of their fertility as well. Mating in the middle of both is a sure fire way to conceive, and while there are contraceptives to prevent that, well, right now, none of us had it in our system,”

 

The hand slowly crept up from Ace’s hip to his rib before going back down, and after a moment, Marco splayed it on top of his abdomen, tracing the hard and muscled planes. His eyes fluttered close as he grunted, and even before looking, Ace could feel the familiar heated sensation of his dick swelling once more. It was a rather captivating sight, to see the older’s cock slowly becoming filled once more, the swell that grew on the base seemingly growing even larger than before in complete vengeance. 

 

Ace slowly let his gaze moved upwards, from that pulsing arousal and to Marco’s taut stomach, to his heaving chest and to his face, once again crumpled in pain. Sweat trickled down from his forehead, and Ace knew it had nothing to do with the room’s temperature. 

 

Ignoring his protesting muscles, the freckled male pushed himself up and wrapped both arms around the man’s shoulders. Marco melted in his hold unresisting, head falling limply on his shoulder, burrowing himself in the area between his shoulder and neck. He was still breathing heavily, heady and tantalizing scent much more pronounced due to their closeness. The scent of an Alpha, Ace thought, finally recognizing it for what it is, his Alpha, who’s been fighting himself from the very second he stepped into this room for Ace’s sake because that’s the kind of man Marco was.

 

“My father is Gol D. Roger,”

 

Maybe it was the post-coital bliss, maybe he’s just out of stamina, or maybe because it was Marco he’s talking to, but the usual trepidation that accompanies this particular topic was barely there. After Pops’ acceptance, he still had his doubts, he still has his fears and insecurity, but right now, he felt none of those. He felt inexplicable trust to this man in his embrace, and thus, he felt the need to comfort and please him the way he had to Ace. 

 

Marco grew stiff in his hold, before relaxing once more, “Well now, i heard he did have a child, but nobody thought they survived,” a pair of arms wrapped around his waist loosely, “Is there a reason you’re telling me, though?”

 

“Does it disgust you?”

 

The head on his shoulder was lifted, and a pair of confused and baffled eyes stared down at him, “Why should i? He was Pops’ rival, but also a friend. I’m amazed to know his son is here with us right now,”

 

There’s not a smidgen of lie in his words. 

 

Ace leaned his head forward, pressing their damp foreheads together and spoke in the same level of sincerity, “If you’re fine with possibly having his grandchildren, then i’m fine with it too,” 

 

The hands on his waist faltered, as Marco let out a strangled gasp. Before he can slither away from his hold, Ace tightened his arms, pulling the blonde even closer, “I grew up hating myself for it, thinking that i don’t deserve to live because of his blood. I become a pirate to become free of it, from myself, but in the end, i can never run away from the fact that no matter how far i run, i can never escape from being his son. I thought i can never be loved for being the child of a demon, until i meet so many people who will accept me as i am. My mother, who gave birth to me despite who i am, my brothers, Pops,” Marco’s struggle died down, and Ace closed his eyes, placing his chin on the crook of his shoulder, “and now, there’s you,”

 

Arms gripped his waist again, gently and trembling as if afraid. Though what Marco is afraid of Ace couldn’t possibly know, “I can’t tell my child self that it’s okay, that there will be people in the future who will love him no matter what,” a small smile graced his face, “But if i have one of my own, i will raise them to know that every single second of their life, they are loved. That they can never be blamed for who they are born to, because it wasn’t their fault for existing,”

 

He shed a tear, followed by another, and it was ridiculous to feel this emotional over a thought that only ever come across him a few seconds ago, but Ace lets himself anyway. He held Marco closer, relishing in their closeness, in the older’s scent and the comfort in the arms that started to grip him harder, pulling him even closer against Marco, “And i can’t think of anyone i want more as the father than you,”

 

“Ace, you’re testing my resolve,” the blonde hissed, sounding like he didn’t have much of it left, “Are you honestly suggesting— You’re still so young, with so many options, with so much life ahead of you. You shouldn’t settle for this decrepit old man, shouldn’t keep giving me hope like this when—“

 

With one hand, Ace guided Marco’s head away from his shoulder and to face him, wanting the man to see his eyes, to meet his gaze, and see that there’s nothing but the truth in his words, “But i want you for a long time now. As a man, as my Alpha, my mate, even as the father of my child, i want all of you, Marco,” he whispered resolutely, “I love you,”

 

Marco let out a noise akin to a wounded animal, the last of his walls of restraint finally crumbling down.

 

Their kiss was a cross between gentle and hard, lustful but loving at the same time. Marco held Ace so closely and tightly, like he was afraid of him changing his mind and slipping away, “I love you too. I shouldn’t have, but i wanted you so badly, you’re all i can think about, and i hate myself for it. For wanting you so much, for wanting to keep someone so free, so out of my reach. Nothing else ever mattered to me, if you ever happen to be another Alpha, if you never returned my feelings, i was fine with it because all i want was just to be close to you,”

 

The churning inside of Ace’s stomach was back, and along with it, the tight feeling in his chest out of elation. 

 

As he was laid back to the bed, suddenly the door was knocked, harshly and repeatedly, “Marco! You better stay away from Ace like you said you would! You need to leave before his next heat hits!” It was Izou, from the sound of it, and distantly in his bleary mind, Ace remembered Marco mentioning that he and Haruta will come by.

 

Before Marco can make a move, Ace slipped out from under the blonde, striding confidently to the door without even caring that he wasn’t wearing a single cloth to cover himself. He opened the door, facing the shocked expression on both commander’s faces, “He’s staying,” he told them, glancing back to the bewildered look sent to him from the bed, “Marco’s staying here with me,”

 

In watching the awed expression on the older’s face, Ace missed the look that crossed between Izou and Haruta. Especially Izou, whose lips curled in amusement, “Is he now?” the kimono-clad commander hummed, leering between the two naked men on the door and on the bed, “Oh, no wonder. I bet everything else will be ruined for you now. First heat and you already got a knot that bi—“

 

“Izou!” Haruta screeched, blushing brightly as he slapped the cackling crossdresser’s arm.

 

Ace tried to say something - mostly trying to shoo them away - when his stomach cramped and he could feel his body once again going feverish. He moaned at the first trickle of slick down his thighs, only barely able to hold himself up against the doorknob until thankfully, he was pulled back against broad chest and held up by strong arms. Even through his slowly clouded eyes, he could see Whitebeard’s mark on the chest he laid his head on, and could distantly hear Haruta’s squeak and Marco’s mutters before the door was slammed close.

 

Before he knew it, he was back on the bed, laid on his back and shivering with every touch. Marco’s kisses and whispers were like a hazy blur, leaving him begging and wanting fulfilment.

 

Ace cried with every finger that entered him, slowly stretching despite his walls feeling loose and ready, and arching his back to every kiss and licks to his torso. Marco shushed him, letting go of his peaked nipple and exposing it again to the air, “I’ll make it good for you this time, make you feel so good,”

 

“I can’t take it anymore,” the younger begged, head tossing from side to side as the fingers inside of him brushed against the very same spot that made him see stars, “Please, give me your knot now, please, Alpha, i need to feel you,”

 

Marco groaned at his request, lifting him up to turn him on all fours. Ace’s arms could barely hold him up anymore, so he let them splayed in front of him, fingertips brushing the headboards and clutching the sheet while the man behind him lifted his hips and rear higher. The fingers has left him, making him feel empty, and with every squeeze of his muscles he could hear squelching sound from his hole that would’ve made him embarrassed any other time he wasn’t so desperate.

 

Finally, when he could feel the older man loomed on his back, Ace sighed, pushing his hips back to the very prominent girth brushing along his crack, “There’s one more thing i need to tell you. Omegas have glands, a scent gland right on the back of their neck,” Marco muttered close to his ear, and he nuzzled close to a spot on Ace’s nape, the same spot the younger remembered him kissing hesitantly against, “It’s where their scent comes from, the scent that will invite Alphas to them, and should an Alpha bite it, made a mark to it, then that means they are bonded and mated,”

 

Despite wanting the chatter to stop and to get on with it, Ace turned his head, catching only a hint of blonde hair, “And if we’re mated?”

 

There’s another shudder in Marco’s breath, and Ace was not blind to the fact that it was because of the thought of biting him, “Then everyone will know you’re mine, as i am yours,”

 

Without even a single hesitation, Ace pushed his shoulder up, propping himself by his elbow and twisting his head even further back as he brushed his hair off from his nape, “Mark me, Marco,”

 

The bite was nothing gentle, in fact it stung like nothing else, but the second the pain began to subside, Ace could feel nothing but unending pleasure wrecking through his entire body. He mewled at the sensation, almost sobbing at how good it feels until Marco bit harder and he came with a loud cry.

 

Ace cursed himself for coming so fast, until Marco thrust into him, knot and all, and sends another jolt of pleasure to his sensitive body. The pleasure was too much, too overwhelming, and with every thrust he began to feel tears streaming down his face and saliva dripping out of his constantly, widely gaping mouth.

 

How unflattering he must’ve looked now, buried too deep in nothing but orgasmic gratification, his lips unable to say anything but crying out Marco’s name - though barely coherent - and moan to the top of his lungs, "Mar- Alpha, Alpha, please-"

 

In the middle of the violent thrusting, it suddenly stopped again, but before Ace could protest, he was turned to his front. Marco looks _wrecked,_ blonde bangs plastered to his forehead and eyes blown wide, and the moment he saw Ace’s teary face, he let out a pinched groan before connecting their lips together, "My Omega," the older panted against his lips, and the exhilaration that erupted in Ace's core at the acknowledgement was unbelievable, "Ace, my Omega, mine, mine,"

 

Their kiss was sloppy and wet, full of saliva, sweat and what else, but Ace returned the gesture just as fervently, spreading his legs as wide as he could while Marco continues to pound into him.

 

Ace came with a shout, spattering both his and the older’s front, and Marco came with what could only be described as an actual _roar,_ buried deep inside of him, knot pressing inside of his rim in a painful but pleasurable way, as he empties everything he had been holding back into Ace’s tight, velvety passage. The dark haired one tossed his head backwards, eyes rolling back at how much he was filled with, but he was so wrung out all he could do was mewl weakly at the sensation.

 

Marco stayed inside of him, the swell of his knot dissipating very slowly. Ace didn’t want it to go away just yet, so he squeezed a little and heard the other man groan, “Don’t do that,”

 

He lifted his head, wanting to apologize, but any words on his tongue died down the moment their eyes met. The dark lust in those blue orbs were fading away, and all that is left is a long, affectionate stare even from behind drooped, tired eyelids, one that he had seen so many times directed to him but never quite understood the meaning of until today. Those orbs disappeared as the eyelids fluttered close, but it was okay, because Ace has closed his own eyes as he leaned in to Marco’s gentle kiss, with only the barest hints of uncertainty.

 

As the separated, fatigue slowly encroach his being, and Ace stifled a yawn. He heard Marco chuckling, before feeling a kiss on his forehead, “Go to sleep. Izou and Haruta will bring us something to eat,”

 

Sleep sounds heavenly right now, and the mention of food reminds Ace that he’s famished, “How much longer does heats goes for?”

 

“On average? You’d be like this for the next 3 or 4 days,” 

 

Ace groaned. Feeling horny and wanting to fuck for an entire 3 or 4 days? He felt like he can’t even survive this one day, “Does it work like that too with ruts?”

 

At this, Marco paused for a moment before burying his face on the crook of his shoulder, nuzzling and pressing butterfly kisses, before saying, “Ruts goes away once the knot is satisfied, actually. At least, it is when i’m unmated,”

 

There’s a hanging implication there that he’s supposed to notice, but Ace’s body and mind were both tired. Still, it wasn’t tired enough to notice that Marco has stopped saying ‘Alpha and Omega’ and instead, finally referred it as both ‘yours and mine’. He liked to think it was a sign that Marco finally accepting that this is happening, that he doesn’t have to keep dodging the fact that he wanted Ace as much as Ace wanted him. After all, they are now mated.

 

His nape gave a dull throb at the reminder, a sensation both thrilling and painful at the same time, “And now that you are?”

 

A soft and fond look crossed Marco’s face at the reminder, before he replied, “I don’t know if it’ll happen immediately, but i’ll knot for as long as my Omega needs it,”

 

When said knot finally fades, Marco pulled out and rolled to his side, pulling Ace’s heaving body close to him. They shared another kiss, once turning into twice, and at the third, Ace couldn’t stop his exhaustion any longer, feeling his eyes slowly fluttering close, “Marco?”

 

“Yes, Ace?” His hand was now wrapped around Ace’s waist, while the other was used as a pillow for the younger. Ace could feel him reaching to his nape, brushing against the bite mark every so often and sending fluttering thrills down his spine.

 

“You’ll be here, won’t you? Through all of it?”

 

The hand brushing his gland and bite mark paused briefly before continuing, slower than before, “I will. Through this heat, the next heat,” the hand on his waist moved to his abdomen, fingertips lightly brushing against the skin, “Through anything the future may have for us,”

 

As his eyes fell close completely, Ace mutters, “I love you,”

 

He fell asleep before he could hear it, but it’s okay, he’ll have more chances in the future to hear Marco’s reply.

 

**Notes for the Chapter:**

> Thinking of making a sequel out of this for my next writer's block. Ofc, this entire thing is just an excuse to write smut...
> 
>  
> 
> Anyway, thank you so much for reading and for your kind words! Please let me know what you think and i hope you liked it!

**Author's Note:**

> I probably didn't do this trope justice, but i hope i do anyway. Still, since this is the first time i i dabble in A/B/O in general, please tell me what you think and give me suggestions!
> 
> Anyway, thank you so much for reading and hope you liked it!


End file.
